Power transmission belt



p 1952 T. ELLISON ETAL 2,608,875

POWER TRANSMISSION BELT Filed'Nov. 2, 1949 0 05g g5 1????TTTIZTIIII'I 25 TELLISOUI nvent OfS Patented Sept. 2, 1952 POWER! TRANSMISSIGN -BELT' -'.l;h .m aEl1ison--and*Sydney George-Denim. Snond01 nearrllerby, Englan assignorsto. British Celancse. Limi ed, a corporation of? Great Bri a n .ApplicatiomNovembers2, 1949, Serial: No.1125,'fl06; .-.In Great:.:Britain Novembenmhzlaifi.

11-01mm. '(01. rig-23.

- .This invention; relates toi- .po.wer. transmission.

elts, particularly-for .variable peed. drives and. is.especiallyconcerned.with V-belts of the type uitable for: use; in association, with smoothrfaced expandingv-pulleys to constitute avariablespeed drive. i

.A common. form of. belt at thi type compris s an endlessjband of. leathen-balataor multirply fabric, which. has secured to its...inner face by nuts and bolts a.series,- ofv aluminiumor wooden bars or lags, the heads of, which project on each side-ct the band. Secured-tmthe outer faces of the projecting heads by means of rivets are leather pads whichzmake'zcontactwith the inner faces ofthe pulley discs. Each pulley compri e two discs, and the inner face of. each disc is in the'form of a fiat cone, having 'a semi-vertical angle of the: order-of 70-80 and the: outer faces of the-heads of the bars are inclined, to conform to;..theefacesz of the pulleydiscs, Belts; of this form are liable to the disadvantages of frequent breakage, particularly of the transverse bars, and of rapid wear and'detachment-ofthe pads, giving rise tgunduly high maintenance costs and freql fim stoppa es. incineration. .ItilS an object of the present invention to provide a V-belt in which these disadvantages are overcome or substantially reduced.

According to the present invention a V-belt comprises a band of flexible material and, secured transversely to one face of said band, a spaced series of bars of a cross-section that, throughout their length, is uniform and of a character suitable for frictional engagement with a pulley surface, the ends of said bars projecting beyond the edges of said band and having exposed end surfaces at an angle to the length of each bar for engagement with the conical face of a V-pulley. Belts so constructed are not subject to the disadvantage that a facing material at the ends of the transverse bars is liable to become detached, while breakage of th bars and unduly rapid wear of the ends thereof due to the rigidity of the bars are substantially eliminated.

A suitable material for making the transverse bars is a narrow V-belting, made up of layers of leather sewn or otherwise secured together. Other forms of thick, narrow belting may, however, be employed, for example V-belting made of layers of textile fabric and rubber. The V-belting is cut to suitable lengths which are secured transversely across the flexible band, with their wider faces in contact with the inner face of the band. A jig can be employed for cutting the V-belting material, so that the pieces are 2': all-euual-in length and their..ends.-.-are,al1, cutito, ascorrectangle;

As the band to, which the. transverse. barsate;

secured, the. materials used previously, imbelts.

Withrigidbaracan beemployed, 82;;8. bands-0t leather, .balataor multi-ply,- fabric... A;flat ,belte ingcomprising several piles of textile-material,

united, together and externally coated.- -with.-.12ub.- her,-v isparticularlysuitalole.

The transverse; barscan. be secured." to;.the-.-

and, as in previous. arrangements; by means of nuts, and. bolts; each. bar: being?- fastened toz-the. band, at, two points; I v of, the: fastening: metal, plates. e. g. of ,rnild. steel...

- organ aluminium alloy. canine-secured on the.

other. side. of. the-band, in register. with, each..ba1'.-

(.e,,.g;, ,two or. three; on. each;side,,.of. the join), withv a. piece .of. material similar, to that, of the band itself, the. endsof theband proper beingbutted.

against. one. another: beneath. the ,additionahpiece.

' Qf. band material.

By. way of, example. onerforirrofv V-belt in acrl cordance with the present invention, and the manner in which it is to be used, will now be described in greater detail with reference to the accompanying drawings, in which,

Figure 1 is a longitudinal section of the belt,

Figure 2 is a lateral section of the belt,

Figure 3 is a side elevation showing a joint in the belt, and

Figure 4 is a diagrammatic plan of a variable speed drive in which the belt is used.

The belt, as shown in Figures 1-3, comprises a band 5 of 4-ply rubberised textile belting having a total thickness of A1 and a width of 4". The four plies 6 of the belt are united together and externally coated with rubber, the edges of the band at I as well as the faces 8 thereof being rubber-covered. The band 5 is drilled at intervals of 2 4" along the length thereof with pairs of holes 9 spaced apart across the width of the band by a distance of 2%". Second to one face of the band by means of these holes is a series of transverse bars It] in the form of narrow lengths of leather V-belting, of maximum width of 1 and a depth of about 1", the non-parallel faces ll of the V-belting being at an angle of 40 to each other. The V-belting consists of layers of leather, sufficient in number and thickness to make up the required depth of 1", and stitched together with copper wire. The bars I ll 01 V-belting are cut to a maximum length of 5%" on the To increase: the; strength.

Wider face H, but the ends I5 thereof are cut obliquely at an angle of 72 to conform to the angle of the V-pulleys with which the belt is to be used, so that the narrower face [6 of each bar is correspondingly shorter than the wider face H. Each bar I is bored, from the narrower face I6 to the wider face it, with two 2 holes, 2%" apart, and is secured with its wider face ll against the band 5 by two mild stee1 roundheaded bolts [1 extending through the holes in the V-belting bars and in the band 5. On the upper side of the band 5 is placed a plate [8 of 1 x 1 mild steel bar, 4" long, drilled with A, holes through which the bolts I? pass, the bolts being secured by a pair of lock nuts [9 engaging with the face of the mild steel plate I8.

A method of joining together the ends of a piece of belting of the kind described above, so as to make an endless belt, is shown in Figure 3. Two of the mild steel plates [8 at each end of the piece are removed (i. e. over the bars indicated at the ends 2| of the band 5 are butted against one another, and a 10" length 22 of rubberised fabric similar to that of the band 5 itself is substituted for the mild steel plates removed, being suitably bored for the passage of the bolts [7 and secured in position by means ofth-e bolts [7 and lock nuts 19. Washers 23 are placed between the lock nuts l9 and the additional piece of rubberised fabric.

The belt of the present invention is applicable to belt and V-pulley drives generally, but is particularly applicable to variable speed drives of the type in which axially expanding pulleys are usedpA drive of this kind is shown diagrammatically in Figure 4, in which two pairs of cones 25 are splined to shafts 26, each pair serving as a pulley for engagement by the endless belt 21. Thesemi-vertical angle of the cones 25 is 72 matching the angle of the ends l5 of the bars in of the belt. Levers 28 serve to bring together one pair of cones 25 while expanding the other, sovarying the radii at which the belt 2'! acts on the two pulleys and varying the speed ratio between the shafts 26. The corners 29 of the bars ID are rounded ofi to avoid a tendency for 2,608,875 1 i j; g 1 f 4 them to cut into the surface of the band 5 when the belt 21 is passing round a small radius.

The belt described above is inexpensive to construct and maintain, and is simple to repair or recondition. The belt runs very quietly and has a very long life without br eakage'or undue wear. The flexibility of the bars in appears to facilitate the passage of the belt round pulleys of small diameter and permits variable speed drives of the type described above to be readily used over their full range of speed ratios.

Having described our invention, What we desire to secure by Letters Patent is:

An endless V-belt comprising a band of flexible material, a spaced series of bars secured by through fastenings transversely to one face of said band, the ends of said band being butted and joined by a piece of similar flexible material secured to the other face of said band by the same fastenings as for at least four of said bars, two on each side of the butt joint and, flat metal plates secured to said other face of said band by the same fastenings as the associated bars, said bars being of a uniform cross-section throughout their length and of a character suitable for frictional engagement with a pulley surface, the ends of said bars projecting beyond the edges of said band and having exposed end surfaces at an angle to the length of each bar for engagement with the conical faces of a Vpulley.

THOMAS ELLISON. SYDNEY GEORGE LEUTY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Great Britain 1910 

